Microwave assisted synthesis, spectroscopic and antibacterial studies of bis(cyclopentadienyl)hafnium(IV) derivatives with benzil bis(aroyl hydrazones)

The reactions of (η5-C5H5)2HfCl2 with benzil bis(hydrazones) (LH2), derived from benzil and aromatic acid hydrazides (benzoic, 2-chlorobenzoic, 4-chlorobenzoic, 2-methylbenzoic or 4-methoxybenzoic) have been studied in anhydrous tetrahydrofuran in the presence of n-butylamine by both conventional methods and by microwave heating. Binuclear complexes of type [{(η5-C5H5)2HfCl}2(L)] were obtained in both cases. Tentative structural conclusions are drawn for the reaction products based upon analyses, electrical conductance, magnetic moment and spectral (UV–vis, IR, 1H NMR and 13C NMR) data. A FAB-mass spectrum of one compound was also recorded to confirm the binuclear structures. Studies were conducted to assess the growth inhibiting potential of the complexes and free ligands against various bacterial strains.